A model approach to climate change

Improvements in computing power since the 1970s have been crucial in allowing additional processes to be included. Although current models typically contain a million lines of code, we can still simulate years of model time per day, allowing us to run simulations many times over with slightly different values of physical parameters (see for example www.climateprediction.net). This allows us to assess how sensitive the predictions of climate models are to uncertainties in these values. As computing power and model resolution increase still further, we will be able to resolve more processes explicitly, reducing the need for parametrization.